Blast-furnace process of producing phosphorus and phosphorus compounds.



snares nr orrron BLAST-FURNACE PROCESS OF PRODUCING PHOSPHORUS'AND PHOSPHORUS COMPOUNDS.-

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To all whom it may concern: Be it known that I, JOHN J. GRAY, JI., a citizen of the United 'States, residing at Rockdale, in the county of Maury and State of Tennessee, have invented certain new and useful Improvements in Blast Furnace Processes of Producing Phosphorus and Phosphorus Compounds; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

' This invention relates to a continuous process of producing in a blast furnace, phosphorus, together with compounds of phosphorus and various metals, and has for its object to provide a method which will attain these results when using natural phosphates in a manner more eficient, and less costly than has been heretofore proposed.

With theseand other objects in view the invention consists in the novel steps and combinations of steps more fully hereinafter disclosed and particularly pointed out in the claims.

In order that the invention may be clearly understood it is said: In my prior Patent No. 831,427 dated Sept. 18, 1906, and entitled Manufacture of form-phosphorus I have referred to various processes of producing ferro-phosphorus prior to said patcut, and I have also disclosed a blast furnace method of producing ferro-phosphorus from natural phosphates. Among other particulars this invention differs from the invention of my said patent and from the disclosure of the prior art in that-its pri mary object is to produce phosphorus or phosphorus ca'rrying vapors from natural phosphates in a blast furnace andits secondary object is to simultaneously produce in such a furnace phosphoreted compounds of phosphorus with the various metals, and metal alloys. It is .well known that it has been heretofore proposed to produce phosphorus itself in a blast'furnace, but no one prior to my invention, so far as I am aware has ever succeeded in producing phosphorus from natural phosphates commercially in a blast furnace and at the same time producing'compounds of phosphorus with various metals or their al oys. It of course has, however, been proposed time and a mum employ the more expensive electric urnace in dealing with natural phosphates in the production of various compounds of phas Specification of Letters Patent.

Patented Jan. 18, 1916,.

Application filed September 7, I915. SerialNo'. 49,359.

proportioning'the charge materials I can employ in a blast furnace successfully on a commercial scale, coke made from coal, and

I have further discovered that if I add a proper proportion of a metal or metal alloy, or of a metal ore to the charge, the process is greatly facilitated, in that the addition of such -metal or metal ore maintains a materials, and to therefore maintain them sufficiently fluid to flow freely from the furnace when they are tapped off. I his fluidity 1 of the slag, further facilitates the escape of the P 0 vapors as will appear below. In general any of the metals that are'usually smelted in a blast furnace will be suitable for this purpose, such for example as iron,

such as coke, charcoal, etc., or other suitable fuel, and to which has been also added lime or limestone, or other basic material, as well as a suitable metal such as iron, iron ores, copper, copper ores, nickel, nickel ores, or

. alloys of said metals, making the necessary provision for air, and using only such quan'- tities of each material as will be necessary to effect the physical and chemical changes which end in the simultaneous production of chemical compounds of phosphorus and'a ter are vconveyed away'and treated under a separate operation to produce phosphorus or phosphorus com ounds.

In carrym out t e invention of course an intimate an accurate analysis should be metal, and of phosphorus vapors, which latfurnace.

made of all .materials constituting the charge so as to accurately'proportion the acidsnnd bases. Only suflicientcoke is used to providesuflicient heat to bring about the desired chemical reactions between the various elements and to produce and maintain in the furnace more than enough carbon monoxid CO, than is necessary'for the de- "oxidation of the phosphorus compounds liberated by the operation. The air is also used in quantities insuflicient to completely ignite the coke or other carbon materials, and only in quantities sufficient to supply the oxygen necessary to the production of the requisite heat in the furnace and to 'form a portion of the carbonvmonoxid. This deoxidizing agent gets part of its oxygen from the air 'andanother part from the compounds liberated by the reactions which take place in the Enough tri-calcium phosphate is used to yield suflicient phosphorus to be ab-. sorbedby the metals or alloys present, and to furnish in addition-suflicient vapors of phosphorus to make thecondensation of the latter commercially profitable. Silica in a suitable form is used as an acid toliberate the phosphoric acid, P 0 of the 1 mineralaphosphate from its alkaline base or bases, and-in suflicient quantities to chemically satisfy said bases, or other compounds fof the mixture, and in additionsuflicient silica isfemployed to produce the desired fluidity. in the slag. I may employ limestone-or other cheap sources of basic matep the quantity. small, as it is best to makethe silicic acid take up as much of the bases rial, in such amounts as are necessary to neutralize the acid materials-present when they are in excess, I also endeavor to make from the phosphates as it is possible to do,

and thus. liberate the highest possible. per;- centage of phosphorus. I

With a charge of the character above, and heated to the high temperatures ofablast furnace the silicic acid attacksthe phosphates, combines with their basic materials, liberates the phosphoric acid P 0 and forms compounds making up the slag. The P 0 thus liberated in a reducing atmosphere'jof' CO, is deoxidized' to phosphorus vapors. The metal or allovs being in insuiiicientquantities to take up more than say 40% or 50% of'the phosphorus liberated, and the; remainder of' thesaid phosphorus having nothing with which itcan combine,"

it passes out with the otherfurnace gases and, maybe subsequently recovered as red phosphorus, as ortho phosphoric acid, or in. any other desired form. In the meantime the metals present" form a molten pool,

whichserves to impart heat to the slag, and therefore. to maintain the latter more fluid than would be' the case if-no'metals were present. Said metals accordingly hot only render the slag more easyito tap from the ing atmosphere.

furnace but it is found vin practice-that their presence causes a greater liberation of P 0 from the molten mass, than would otherwise take place. probably mechanically held inthe slag and molten mass, owing to its high surface ten- In other words, the P Q is sion, and the more fluid is the slagqthe more readily does such vapors escape therefrom.

The-phosphoreted. metals may be tappedout at the bottom of the furnace and run 011' as is pigiron, or ferrp-phosphorus, and

the slag is also run off at regular intervals,

' in a manner well known.

A more definite understanding of my 7 I process will be had from the following: About eight pounds of air will ignite say two thirds of avpound of coke, to form G0 and will alsooxidize say. one third of a pound of coke to form CO. I have foundthat by using preheated air at the rate of say eight pounds to one pound of coke, and

thus producing CO and CO gases as above mentioned, and using coke to the amount of say 40% of the total charge, I will get sulficient heat'for the desired reactions and in addition I will obtain sufiicient CO gas to maintain at all times the necessaryv reduczone, the-process is rendered continuous.

The heated or molten metal which is being continuously heated and melted above the fusion Zone, drips through or comes into. contact with the rising phosphorus vapors,

and absorbs said vapors to form various metal phosphids.

If the. ordinary natural phosphates and iron ore are employed a specific charge may -be prepared as follows: Using for example a phosphate rock consisting of say 7 5% tricalcium phosphate having 40% CaO combined with P 0 to form the Ca .P. ,O and supposing 16% of said rock consists of carbonates, sulfates and fiuorids of calcium, .while say 4%% of. said rock consists of silica,

Si'(),,, and; say 44 consists of F e 0 the proportions of the charge would be as follows: air, 1472pounds; coke, 184 pounds; natural phosphates, 140 pounds; sand' or flint" (containing S10 64. pounds; iron ore (containing 50% 'Fe and v18% SiO 60 pounds; CaCO (if found necessary on account of incomplete reactions),

.12 pounds.

By thus maintaining the Supposing the reactions are all complete I the/184 pounds of coke considered as purevcarbon would in its major part ignite to form CO "gas with the oxygen of the air,

1,1es,49a

and thereby produce the desired temperature in the furnace. This said coke would also in its minor part combine with the remaining oxygen of the air, as well as with some of the oxygen of the evolvedcompounds to form suflicient CO gas to reduce all the deoxidizable compounds ofthe charge, while the gases discharged from the furnace will contain suflicient heat to preheat the air employed for a succeeding charge if they are passed through the usual stoves.

The various constituents of the charge maybe stated to react about as follows: 105

pounds of tri-calcium phosphate, together with the 22.4 pounds of calcium fluorid, calcium carbonate and calcium sulfate that are physically combined with the tri-calcium phosphate are decomposed by the silicic acid present. Of this acid 6.3 pounds are carried by the phosphate rock, 10. 8 pounds are carried in theiron ore, and 57.6 are carried by the sand. In all 7 5 pounds of the SiO combine with the total pounds of CaO present to form 145 poundsof CaSiO and thus cause the liberation of 48.9 pounds of P 0 as well as 8.4 pounds of fiuorin, car bonic acid gas and sulfur dioxid. This P 0 is, of course, at once deoxidized in the reducing atmosphere to-form 21 pounds of phosphorus, the CO present thus takingup 27.09 pounds of oxygen from the P 0 Ihe 30 pounds of iron present coming into contact with the 21 pounds of phosphorus vapor absorbs 8. 1 pounds of phosphorus to form 38. 1 ounds. of iron phosphids such as FeP, Fe and Fe,P which together will contain say 22% of phosphorus. The 30 pounds of iron having absorbed 8.4 pounds of phosphorus the remaining 12.6 pounds of phosphorus goes over as vapors with the other gases, and may be recovered as red phosphorus or in any desired form. Accordingly, after having started the furnace with 1-172 pounds of air, 184 pounds of, coke,

110 pounds of phosphate rock, 64 pounds of sand or flint and 60pounds of iron ore, or a total of 1920 p unds, the reactions being complete, I end ,with 1691 pounds of gases (some or all of which may be used to pre. heat the succeeding charge of air), as well as with 12.6 pounds-of phosphorus vapors,

38.4 of iron phosphids and 178 pounds of- CaSiO In practice these reactions are to a slight degree varied by differing temperatures and by differing physical and mechanical conditions. The reactions between the tri-calcium phosphate and the silica are really never complete, for a small amount of the phosphoric acid always becomes en tangled in the slag mass which probably takes on more lime thanwould otherwise he the case, instead of releasing that present, and probably for this and other reasons the slag sometimes becomes too and and gives trouble around-the twyers. Here the i use of a small amountof'carbonate of lime becomes of great importance, for by using' the above mentioned 12 pounds of CaCO significant complications involving complex chemical compounds, but they do not materially change or interfere with the process.

It will thus be seen that by following the foregoing process I avoid the great objection which othershave encountered in attempting to produce phosphorus from natural phosphates in a blast furnace and which is caused by the materials being too refractory to be handled in the 'old way. I' avoid this objection largely. by the use of the metals or ores or the alloys above mentioned which seems to render the slag as well as the molten mass more fluid at the-point of discharge than would otherwise be the case at the temperatures of a blast furnace and.

phosphoreting of metallic'copper its alloys and copper ores but of course in that case the proportions of the charge given above would have to be varied as it would be when other metals or their alloys are employed. In all cases it is very desirable that an experienced furnace man carry out the process, and that an intimate accurate chemical knowledge of all the materials be had.

It is evident that by increasing the quantity of phosphate rock and silica and coke, or by decreasing the amount of iron and coke used in the process, I can produce a surplus of phosphorus vapor or bymaking other obvious changes I. can lessen the quantity. ofphosphorus vapor produced at will.

Since when employing various metals and ores the problem is one largely a matter of ited to the above disclosure, except as may be required by the claims. In fact it is clear. that instead of a major portion of the phosphorus vapors being allowed to leave the furnace, and a lesser portion being taken up by the metals these proportions may be reversed and a major portionof. the phos phorus vapors may be taken up by the metto produce the desired fluidity in the slag' but insufficient to take up all the liberated phosphorus, and sufiicient carbon to produce'the desired reacting temperature as well as a reducing atmosphere in thei furnace; and feeding to said charge only suf-' ficientair to produce said temperature and reducing atmosphere, substantially as de= scribed. I

2. The process of simultaneously producing phosphorus and metal phosphids from a natural phosphate in a blast furnace, which consists in charging said furnace with a suitable mixture containing said phosphate, sufficient silica to liberate the desired amount of phosphorus, metal 'suflicient'to make the desired amount of phosphids and to produce the desired fluidity in the slag but insufficient to take upmore than eighty.

per cent. of the liberated phosphorus, and sufiicient carbon to produce the desired reacting temperature as well as a reducing atmosphere in the furnace;;and feeding. to said charge only suficien't air to produce said temperature and reducing atmosphere, substantially as described. i

3. The process of simultaneously producing phosphorus and phosphids which consists in charging a blast furnace with a mixture containing a natural phosphate, sufficient silica to liberate .a predetermined quantity of phosphorus, metal in the form of an ore sufficient to take up a predetermined per cent. of the liberated phosphorus and to produce the'desired fluidity 1n the slag, but insufiicient to take up a predetermined other quantity of said phosphorus, and sufficient carbon to bring about the desired reactions while supplyinga reducing atmosphere in the furnace, and so controlling the air fed to the furnace as to maintain said reducing atmosphere therein, substantially as described.

I 4'. The process of simultaneously producing phosphorus and phosphids which consists in charging a blast furnace with a mixture containing a natural phosphate, sufficient silica' to liberate ,a predetermined quantity of phosphorus, metalin the form of an ore sufiicient to take up more than'ten per cent. of the liberated phosphorus and to produce the desired fluidity in the slag butinsuficient to take up a substantial major quantity of said phosphorus,; and suflicient carbon to bring about the desired reactions and to supply a reducing atmosphere in the furnace ;'and so controlling the air fed 'to the furnace as tomaintain said reducing atmosphere therein, and adding to said charge, when found necessary: a small quantity of a basic material to, render the slag more fluid.

I 5 The process of simultaneously producing phosphorus'and" phosphids which consists in charging a blast furnace with a/miX- ture containing a natural phosphate, sufficient silica to liberate a predetermined quantity of phosphorus, iron sufficient to take up more than ten per cent. of the liberatedphosphorus, but insufficient to take.

up a predetermined ,major quantity of said liberated phosphorus, and sufficient carbon I to bring about the desired reactions. while supplying a reducing atmosphere in the furnace; and so controlling the air fed to the furnace as to maintain said reducing atmosphere therein, substantially as described. I 6. The process of simultaneously producing phosphorus and phosphids which consists in charging a blastfurnace with predetermined quantities of a phosphate, silica, carbon, and a metal in a suitable form; and causing the contained phosphorus to be libs erated and a predetermined portion thereof to enter'said metal and a predetermined portion to leave the furnace. in the form of a vapor,substantially as described.

In testimony whereof I aflix my signature, in presence of two witnesses. I JOHNJ. GRAY, JR.

Witnesses:

HYIJEMAITA. WEBSTER, D. R. GRAY. 

